This disclosure generally relates to drilling a subterranean well for the recovery of hydrocarbons. More particularly, this disclosure relates to power swivels for drilling a subterranean wellbore.
A power swivel is used to drive rotation of a tubular drill string and the drill bit attached to its end so as to form or extend a subterranean wellbore. The power swivel may be driven, in at least some examples, by a hydraulic motor that transfers torque through a gear box to the drill string and the attached drill bit. In addition, the power swivel may include a washpipe assembly that conducts fluid (e.g., drilling fluids) from a source and into the tubular string. While routing the fluid into the drill string, the washpipe provides a sealed connection between the rotating and non-rotating components of the power swivel during drilling operations.